Electrically conductive coupling



April 16, 1968' 1 E. EICHENBERGER ET AL 3,378,813

ELECTRICALLY CONDUCTIVE COUPLING Filed Jan. 4, 1966 I /n l/h 70/15 2H7if Z/ZA an 6/191- gwwy 3%)? 0 United States Patent 3,378,813ELECTRICALLY CONDUCTIVE COUPLING Ernst Eichenberger and Rudolf Ramel,Wettingen, Aargau, Switzerland, assignors to Motor-Columbus A.G., Baden,Aargau, Switzerland, a corporation of Switzerland Filed Jan. 4, 1966,Ser. No. 518,694 Claims priority, application Austria, Jan. 15, 1965,314/65; Nov. 19, 1965, 10,436/ 65 8 Claims. (Cl. 339-255) ABSTRACT OFTHE DISCLOSURE This invention relates to couplings for connectingelectrical conductors, and particularly to a coupling of theplug-and-socket type in which a plug or male coupling member may beinserted into a recess of a socket or female member for connectingconductors attached to the coupling members.

An object of the invention is the porvision of a coupling particularlyuseful for connecting rigid conduc tors and allowing for limitedrelative movement of the conductors due to thermal expansion andcontraction and the like without impairing the conductivity of thecoupling.

Another object is the provision of a coupling suitable for carryingheavy currents, yet capable of being engaged in a simple manner withoutrequiring tools nor much manual effort.

With these and other objects in view, as will become apparenthereinafter, the invention in one of its aspects mainly resides in theprovision of a resilient contact arrangement including several stacks ofspring wire, each stack having several wire turns elongated in thedirection of inward and outward movement of the plug in the recess ofthe socket. The plug and socket have respective conductive faces whichspacedly face each other when the plug is inserted in the recess of thesocket. The contact arrangement is secured to one of these faces in sucha position that the two longitudinal portions of each turn abut-tinglyengage the two conductive faces when the plug is in the recess of thesocket, the turn portion engaging the plug being spaced inward of therecess from the turn portion engaging the socket. When the "longitudinalportions of a turn simultaneously abuttingly engage the afore-mentionedconductive faces, each turn is resiliently deformed from its relaxedcondition.

The turns of each stack are juxtaposed transversely of the direction ofplug movement and transversely of the afore-mentioned inward direction,and the stack as such is elongated in the direction of plug movement,and its length is greater than its width, and greater than its heightwhich is in the afore-mentioned inward direction.

Each stack is secured to the associated conductive face by a frame whichis open in the inward direction and oppositely thereto, and Whose heightis smaller than that of the received stack. The several stacks arepreferably spacedly distributed in a plane perpendicular to thedirection of plug movement. The ratio of length and height of each turnmust be at least 2:1, but is preferably between 5:1 and 8:1 for bestresults.

Other features, additional objects, and many of the attendant advantagesof this invention will be readily appreciated as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawing in which:

FIG. 1 shows a detail of the coupling of FIG. 2 in enlarged perspectiveview;

FIG. 2 shows a disengaged coupling of the invention in side elevation;and

FIG. 3 shows the coupling of FIG. 2 in the engaged condition in sectionon a line corresponding to line III-III in FIG. 2.

Referring now to the drawing in detail, there is seen a coupling of theinvention including a solid, cylindrical, conductive plug 109 and atubular, cylindrical, conductive socket 111 whose internal diameter isgreater than the external diameter of the plug 109. In the engagedposition of theco upling in which the male plug 109 is coaxiallyreceived in the bore of the female socket 111 contact between thecoupling members is provided by multiple spring stacks 101 of which oneis shown in FIG. 1 in perspective view. The stack consists of amultiplicity of identical wire turns each of which is substantiallyelliptic in the relaxed condition illustrated. The several turns have acommon perpendicular axis and are axially contiguous-1y juxtaposed. Theheight 105 of the stack is less than one fifth of its length, the heightand length of the stack corresponding to the major and minor axes of theellipse formed by each turn. The stack has about 15 turns ofsilver-plated round beryllium copper wire, and the width of the stackperpendicular to its height and length is greater than the height, butsmaller than the length.

The stack is enveloped by a frame 103 which extends about the stack inthe direction of length and width of the latter, but is open in thedirection of stack height. The corresponding height 107 of the frame 103is smaller than the height 105 of the stack. The narrow walls of theframe 103 have marginal recesses 1-15 the purpose of which willpresently become apparent.

FIGS. 2 and 3 show two groups of spring stacks 101 arranged inrespective annular zones 113 of the plug 109 and axially secured byretaining rings 117. Each stack 101 is held in its frame 103 which isoriented in such a manner that its longitudinal Walls extends in thedirection of the plug axis and abuttingly engage the plug surface. Therecesses 115 in the narrow walls of the frame 103 accommodate thecurvature of the: plug surface as best seen in FIG. 3.

The several turns of each stack 101 are elongated in the direction ofthe plug axis, and each turn projects from the associated frame 103 inopposite radial directions simultaneously to engage the plug and thesocket 111 under compressive stress. The rings 117 are radiallydimensioned to guide the plug 109 during coaxial insertion into thesocket 111. It will be appreciated that the outer faces of the severalspring stacks 101, when in the relaxed condition, define a cylindricalsurface [having a greater diameter than the internal diameter of thesocket 111. When compressed, their turns are approximately kidneyshaped.

The stacks 101 and the associated frames 103 may be employed withplug-and-socket type couplings whose members may have any configuration,and the showing of cylindrical members in FIGS. 2 and 3 will beunderstood to be merely illustrative. The number of stacks 101 whichoccupy but very little space may be selected freely to obtain thenecessary current-carrying capacity. The useful length of life of thespring stacks 101 depends to a substantialy extent on the orientation ofthe wire turns in the direction of relative movement of the couplingmembers during engagement and disengagement.

It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention, and that it isintended to cover all changes and modifications of the examples of theinvention herein chosen for the purpose of the disclosure which do notconstitute departures from the spirit and scope of the invention setforth in the appended claims.

We claim:

1. A conductive coupling comprising, in combination:

(a) a male coupling member;

(b) a female coupling member formed with a recess therein, said recessbeing shaped for inward and outward movement of said male couplingmember in said recess in a predetermined direction,

(1) said coupling members having respective conductive faces extendingin said direction and spacedly facing each other when said male couplingmember is inserted in said recess;

() resilient contact means including a plurality of stacks of springwire,

(1) each stack including a plurality of wire turns elongated in saiddirection, each turn having two longitudinal portions; and

(d) securing means securing said contact means to one of said faces in aposition in which one of said longitudinal portions of each turnabuttingly engages said one face, the other longitudinal portion of eachturn being spaced from said one portion in a direction inward of saidrecess for abutting engagement with said other face when said malecoupling mem bet is in said recess,

(1) each of said turns being resiliently deformed from the relaxedcondition thereof when simultaneously abuttingly engaging said faces.

2. A coupling as set forth in claim 1, wherein said turns are elliptic.

3. A coupling as set forth in claim 1, wherein the length of each turnis at least twice the greatest dimension of the turn at right angles tothe direction of elongation thereof.

4. A coupling as set forth in claim 1, wherein the length of each turnis between five and eight times the greatest dimension of the turn atright angles to the direction of elongation thereof.

5. A coupling as set forth in claim 1, wherein said 4 turns of eachstack are juxtaposed transversely of the direction of elongationthereof, and transversely of said inward direction, the tack beingelongated in said predetermined direction, and the length thereof beinggreater than the width thereof and greater than the height thereof insaid inward direction.

6. A coupling as set forth in claim 5, wherein said securing meansinclude a plurality of frames, each frame being open in said inwarddirection and oppositely there to, and receiving a respective stacktherein, the height of said frame in said inward direction being smallerthan the height of the received stack.

7. A coupling as set forth in claim 6, wherein said securing meanssecure said stacks to said one face in a common plane perpendicular tosaid predetermined direction in spaced relationship, said one facehaving an annular zone in said plane, said stacks being substantiallyuniformly distributed over said zone.

8. A coupling as set forth in claim 6, wherein said one conductive faceis of convexly arcuate across section about an axis extending in saidpredetermined direction, said frame has two axial walls and two narrowwalls transverse of said axial walls and connecting the same, eachnarrow wall having a recess accommodating the curvature of said oneface.

References Cited UNITED STATES PATENTS 1,236,766 8/1917 Rowe 339-2422,154,275 4/1939 Linn. 2,280,728 4/1942 Streib 339-256 2,379,047 6/ 1945Thomas. 2,521,722 9/1950 Hubbell et a1. 339-248 2,882,514 4/1959 Kr-antz339-256 3,064,107 11/1962 Date 339-255 X 3,087,038 4/1963 Bethke339--255 X FOREIGN PATENTS 524,663 12/1953 Belgium.

997,233 9/1951 France. 1,071,799 12/1959 Germany.

Ad. 29,822 1914 Great Britain. 186,526 10/ 1922 Great Britain.

MARVIN A. CHAMPION, Primary Examiner. P. TEITELBAUM, Assistant Examiner.

